This invention relates to a voltage level judging device for informing the user whether the time has come to exchange or recharge a power source such as a battery for an electrical apparatus.
Among electrical apparatus requiring a power source such as a battery for supplying a voltage of a specified level, there are those which are provided with means for giving the user a warning when the voltage level of such a power source drops to a predetermined level. Among the warning devices of this type, there are those designed to switch on a yellow warning lamp if the voltage level of the source being monitored is below its standard level but above a certain specified level and to switch on a red lamp and stop the operation of the apparatus if the source voltage is below this specified level. In order to output two such warning signals according to two separate criteria, prior art devices of this type use two voltage level detection circuits to compare the source voltage with two reference levels but, if use must be made of two voltage level detection circuits, the associated peripheral circuits become complicated and the apparatus as a whole becomes expensive to manufacture.